JP6401550B2 - Breaker, safety circuit including the same, and secondary battery circuit. - Google Patents

Description

  The present invention relates to a small breaker or the like built in a secondary battery pack or the like of an electric device.

  Conventionally, a breaker is used as a protection device (safety circuit) for secondary batteries and motors of various electric devices. When the temperature of the secondary battery during charging / discharging rises excessively, or when an abnormality occurs such as when an overcurrent flows through a motor or the like equipped in a device such as an automobile or home appliance, Cut off current to protect secondary batteries and motors. Breakers used as such protective devices operate accurately following temperature changes (having good temperature characteristics) and have stable resistance when energized to ensure the safety of the equipment. It is required to be.

  The breaker is provided with a thermally responsive element that operates according to a temperature change and conducts or cuts off a current. Patent Document 1 discloses a breaker to which a bimetal is applied as a thermally responsive element. Bimetal is an element that is formed by laminating two types of plate-like metal materials having different coefficients of thermal expansion, and controls the conduction state of the contact by changing the shape in accordance with a temperature change. The breaker shown in the same document is a case in which parts such as a fixed piece, a movable piece, a thermally responsive element and a PTC thermistor are housed in a case, and terminals of the fixed piece and the movable piece are connected to an electric circuit of an electric device. Used.

WO2011 / 105175 gazette

  In the breaker disclosed in Patent Document 1, the fixed piece is embedded in a case body made of resin by insert molding (see paragraph (0031) of the same document). On the other hand, the movable piece, the thermally responsive element, and the PTC thermistor are accommodated in an opening provided in the case body. A lid member is attached to the opening in which the movable piece, the thermally responsive element, and the PTC thermistor are housed, and the case body and the lid member are fixed by ultrasonic welding or the like (see paragraph (0037) of the same document). . Furthermore, the movable piece is fixed by being sandwiched between the case main body and the lid member at the fixed portion (see paragraph (0032) of the same document).

  However, during the ultrasonic welding, the resin melted from the case main body protrudes from the fixing surface between the case main body and the fixed portion of the movable piece and becomes a resin flash. If the resin beam protrudes greatly into the opening of the case main body, it may interfere with the edge of the heat responsive element and hinder the operation of the heat responsive element.

  The present invention has been made to solve the above-described problems, and an object of the present invention is to provide a breaker that can ensure a good current interruption operation by ensuring a smooth operation of the thermally responsive element.

  In order to achieve the above object, a first invention of the present invention includes a fixed piece having a fixed contact, a movable contact at a tip, and a movable piece that presses and contacts the movable contact with the fixed contact; A heat-responsive element that operates the movable piece so that the movable contact is separated from the fixed contact by being deformed in accordance with a temperature change, and a resin-made first case having an opening for accommodating the heat-responsive element And a second case fixed to the first case in order to close the opening, the movable piece includes a sandwiching portion sandwiched from the back and front by the first case and the second case. And the first case has a fixing portion that is fixed to the back surface of the clamping portion so as to face the opening, and the fixing portion has the thermal response. Opposite the edge of the element In-band, it has a recess for recessed from a peripheral region, wherein the depressed portion is characterized by being formed retracted to the outside of the opening from the edge.

  According to a second aspect of the present invention, there is a fixed piece having a fixed contact, a movable contact at the tip, a movable piece that presses the movable contact against the fixed contact, and is deformed in accordance with a temperature change. To close the opening, a thermally responsive element that operates the movable piece so that the movable contact is separated from the fixed contact, a first case made of resin having an opening for accommodating the thermally responsive element, and And a second case fixed to the first case, wherein the movable piece has a sandwiching portion that is sandwiched from the front and back by the first case and the second case, The first case is formed with a fixing portion that is fixed to the back surface of the sandwiching portion so as to face the opening, and the back surface of the sandwiching portion is formed on an edge of the thermoresponsive element. In the opposite area, Wherein the recess of recessed from the side region is provided.

  In the breaker according to the present invention, an edge of the thermally responsive element has a protruding portion protruding toward the clamping portion, and the depressed portion is formed in a region facing the protruding portion. desirable.

  A safety circuit for an electric device according to the present invention includes the breaker.

  The secondary battery circuit according to the present invention includes the breaker.

  According to the breaker of the first invention, the movable piece and the thermally responsive element are accommodated in the resin-made first case from the opening, and the opening is closed by fixing the second case to the first case. The movable piece has a clamping portion that is clamped from the front and back sides by the first case and the second case, and is accommodated on the front side of the thermally responsive element. In the first case, a fixing portion that is fixed to the back surface of the sandwiching portion is formed facing the opening, and the movable piece is firmly fixed to the first case and the second case. Since the fixing portion has a recessed portion that is recessed from the peripheral region in a region facing the edge of the thermally responsive element, the fixing portion is generated when the holding portion of the movable piece and the fixing portion of the first case are fixed. The flash which is the protrusion of the fixing material can be accommodated in the depression. Thereby, the protrusion of the flash to the opening of the first case is suppressed, and interference between the thermally responsive element and the flash during the current interrupting operation is avoided. Therefore, the smooth operation of the thermally responsive element and hence the movable piece is ensured, and a good current interruption operation can be secured.

  According to the breaker of the second invention, the movable piece and the thermally responsive element are accommodated in the first case made of resin from the opening, and the opening is closed by fixing the second case to the first case. The movable piece has a clamping portion that is clamped from the front and back sides by the first case and the second case, and is accommodated on the front side of the thermally responsive element. In the first case, a fixing portion that is fixed to the back surface of the sandwiching portion is formed facing the opening, and the movable piece is firmly fixed to the first case and the second case. Since the back surface of the sandwiching portion has a recessed portion that is recessed from the peripheral region in a region facing the edge of the thermal response element, when the sandwiching portion of the movable piece and the securing portion of the first case are secured The flash which is a sticking material sticking out can be accommodated in the depression. Thereby, the protrusion of the flash to the opening of the first case is suppressed, and interference between the thermally responsive element and the flash during the current interrupting operation is avoided. Therefore, the smooth operation of the thermally responsive element and hence the movable piece is ensured, and a good current interruption operation can be secured.

The assembly perspective view showing the schematic structure of the breaker by one embodiment of the 1st invention of the present invention. Sectional drawing which shows the said breaker in a normal charge or discharge state. Sectional drawing which shows the said breaker in the overcharge state or the time of abnormality. The perspective view which shows the structure of the case main body applied to the said breaker. The top view which shows the said case main body in which the PTC thermistor and the thermal responsive element were integrated. Sectional drawing which expands and partially shows the process by which a cover member is mounted | worn and fixed to a case main body. The top view which shows the modification of the said thermoresponsive element and a case main body. The top view which shows another modification of the said thermoresponsive element and a case main body. The perspective view which shows the structure of the movable piece applied to the breaker by one Embodiment of 2nd invention of this invention. The top view which shows the structure of the secondary battery pack provided with the said breaker of this invention. The circuit diagram of the safety circuit provided with the said breaker of this invention.

  A breaker according to an embodiment of the first invention will be described with reference to the drawings. 1 to 3 show the configuration of the breaker. The breaker 1 includes a fixed piece 2 having a fixed contact 21, a movable piece 4 having a movable contact 41 at the tip, a thermally responsive element 5 that deforms with a temperature change, a PTC (Positive Temperature Coefficient) thermistor 6, The fixed piece 2, the movable piece 4, the thermally responsive element 5, and a case 7 for housing the PTC thermistor 6 are configured. The case 7 includes a case main body (first case) 71, a lid member (second case) 81 attached to the upper surface of the case main body 71, and the like.

  The fixed piece 2 is formed by, for example, pressing a metal plate mainly composed of copper or the like (in addition, a metal plate such as a copper-titanium alloy, white or brass), and insert-molding the case main body 71 by insert molding. Embedded. A terminal 22 electrically connected to an external circuit is formed at one end of the fixed piece 2, and a support portion 23 that supports the PTC thermistor 6 is formed at the other end side. The PTC thermistor 6 is placed on the convex protrusions (dowels) 24 formed on the support portion 23 of the fixed piece 2 and supported by the protrusions 24.

  The fixed contact 21 is located at a position facing the movable contact 41 by, for example, cladding, plating or coating of a conductive material such as copper, silver alloy, gold-silver alloy in addition to silver, nickel, nickel-silver alloy. It is formed and exposed from a part of the opening 73 a formed inside the case main body 71. The terminal 22 protrudes outward from the edge of the case body 71. The support portion 23 is exposed from an opening 73 d formed inside the case main body 71.

  In the present application, unless otherwise specified, in the fixed piece 2, the surface on which the fixed contact 21 is formed (that is, the upper surface in FIG. 1) is the front surface and the opposite surface. Is described as the back side. The same applies to other parts, for example, the movable piece 4 and the thermally responsive element 5.

  The movable piece 4 is disposed on the front side of the thermally responsive element 5. The movable piece 4 is formed in an arm shape symmetrical to the center line in the longitudinal direction by pressing a plate-like metal material. As a material of the movable piece 4, for example, a material mainly composed of copper or the like equivalent to the fixed piece 2 is preferable. In addition, a conductive elastic material such as copper-titanium alloy, white or brass may be used.

  A movable contact 41 is formed at the tip 4 e on one end side of the movable piece 4. The movable contact 41 is formed of the same material as that of the fixed contact 21, and is joined to the distal end portion 4e of the movable piece 4 by a technique such as clad or crimping in addition to welding. A terminal 42 that is electrically connected to an external circuit is formed on the other end side of the movable piece 4.

  The movable piece 4 includes a sandwiching portion 43, a first elastic portion 44, and a second elastic portion 45 between the movable contact 41 and the terminal 42. The movable piece 4 is fixed by being sandwiched between the case main body 71 and the lid member 81 in the holding portion 43, and the first elastic portion 44 is elastically deformed, so that the movable contact 41 formed at the distal end portion 4e becomes the fixed contact 21. The fixed piece 2 and the movable piece 4 can be energized.

  The second elastic part 45 is formed between the clamping part 43 and the terminal 42. In the present embodiment, the elastic coefficient of the second elastic part 45 is set to be lower than the elastic coefficient of the first elastic part 44 by providing the circular through hole 46 and the constricted part 47 between the clamping part 43 and the terminal 42. Has been. Here, the elastic modulus means a rate of change of strain corresponding to the stress, and the direction of the stress is not particularly limited. The fact that the elastic coefficient of the second elastic portion 45 is lower than that of the first elastic portion 44 means that when an external force that does not destroy the movable piece 4 is applied to the terminal 42, the second elastic portion 45 is more elastic than the deformation in the first elastic portion 44. The deformation in the portion 45 is large. Furthermore, in this embodiment, since the movable piece 4 is firmly fixed in the clamping part 43 between the second elastic part 45 and the first elastic part 44, the stress generated in the second elastic part 45 is the first stress. Almost no transmission is made to the elastic portion 44, and no deformation occurs from the first elastic portion 44 to the movable contact 41.

  The movable piece 4 is curved or bent at the first elastic portion 44 by press working. The degree of bending or bending is not particularly limited as long as the thermally responsive element 5 can be accommodated, and may be appropriately set in consideration of the elastic force at the operating temperature and the return temperature, the pressing force of the contact point, and the like. In addition, a pair of protrusions (contact portions) 44 a and 44 b are formed on the back surface of the first elastic portion 44 so as to face the thermally responsive element 5. The protrusions 44a and 44b and the thermally responsive element 5 come into contact with each other, and the deformation of the thermally responsive element 5 is transmitted to the first elastic portion 44 through the protrusions 44a and 44b (see FIGS. 1, 2 and 3).

  The thermally responsive element 5 has an initial shape curved in an arc shape, and is formed by laminating thin plate materials having different thermal expansion coefficients. When the operating temperature is reached due to overheating, the curved shape of the thermally responsive element 5 is reversely warped with a snap motion, and is restored when the temperature falls below the return temperature due to cooling. The initial shape of the thermoresponsive element 5 can be formed by pressing. As long as the first elastic portion 44 of the movable piece 4 is pushed up by the reverse warp operation of the thermal response element 5 at the desired temperature and returns to the original state by the elastic force of the first elastic portion 44, the material and shape of the thermal response element 5 Is not particularly limited, but a rectangle is desirable from the viewpoint of productivity and efficiency of reverse warp operation, and a rectangle close to a square is desirable in order to efficiently push up the first elastic portion 44 while being small. . Examples of the material of the thermally responsive element 5 include, for example, white, brass, and stainless steel including copper-nickel-manganese alloy or nickel-chromium-iron alloy on the high expansion side and iron-nickel alloy on the low expansion side. A laminate of two types of materials having different coefficients of thermal expansion made of various alloys such as steel is used in combination according to the required conditions.

  The PTC thermistor 6 is disposed between the fixed piece 2 and the thermally responsive element 5. That is, the fixed piece 2 is positioned directly below the thermal actuator 5 with the PTC thermistor 6 interposed therebetween. When the energization of the fixed piece 2 and the movable piece 4 is interrupted by the reverse warping operation of the thermal response element 5, the current flowing through the PTC thermistor 6 increases. As long as the PTC thermistor 6 is a positive temperature coefficient thermistor that limits the current by increasing the resistance value as the temperature rises, the type of operation current, operation voltage, operation temperature, return temperature, etc. can be selected as necessary. The material and shape are not particularly limited as long as these properties are not impaired. In the present embodiment, a ceramic sintered body containing barium titanate, strontium titanate or calcium titanate is used. In addition to the ceramic sintered body, a so-called polymer PTC in which conductive particles such as carbon are contained in a polymer may be used.

  The case body 71 and the lid member 81 constituting the case 7 are made of, for example, a thermoplastic resin such as flame retardant polyamide, polyphenylene sulfide (PPS), liquid crystal polymer (LCP), polybutylene terephthalate (PBT) having excellent heat resistance. It is molded by. A material other than the resin may be applied as long as characteristics equal to or higher than those of the above-described resin can be obtained.

  The case main body 71 is formed with a housing recess 73 for housing the movable piece 4, the thermally responsive element 5, the PTC thermistor 6 and the like. The housing recess 73 has openings 73 a and 73 b for housing the movable piece 4, an opening 73 c for housing the movable piece 4 and the thermally responsive element 5, an opening 73 d for housing the PTC thermistor 6, and the like. doing. The opening 73a is provided to accommodate the distal end of the movable piece 4 and the movable contact 41, and to secure a movable region thereof. The opening 73 b is provided to accommodate the sandwiching portion 43 and the second elastic portion 45 of the movable piece 4. The opening 73c is provided to accommodate the thermally responsive element 5 and to secure a movable region thereof. The opening 73 d is provided to accommodate the PTC thermistor 6. By attaching the lid member 81 to the case body 71, the openings 73a, 73b, 73c and 73d are closed. Note that the edges of the movable piece 4, the thermally responsive element 5, and the PTC thermistor 6 incorporated in the case main body 71 are in contact with each other by a frame formed inside the housing recess 73, and the opposite side of the thermally responsive element 5. It will be guided at the time.

The opening 73 b is formed in a shape corresponding to the second elastic part 45 of the movable piece 4. In addition, a protrusion 74 that protrudes toward the lid member 81 is provided at the bottom of the opening 73b. The protrusion 74 is
When the movable piece 4 is assembled into the case body 71, the movable piece 4 is inserted into the through hole 46 of the movable piece 4. Thereby, the movable piece 4 is easily and accurately positioned with respect to the case main body 71.

  A cover piece may be embedded in the lid member 81 by insert molding as necessary. The cover piece is formed by pressing a metal plate mainly composed of copper or the like, or a metal plate such as stainless steel. The cover piece contributes to downsizing of the breaker 1 while increasing the rigidity and strength of the cover member 81 and thus the case 7 as a casing. Resin is arranged on the outer surface side of the cover piece.

  As shown in FIG. 1, a lid member 81 is formed so as to close the openings 73a, 73b, 73c and 73d and the like of the case main body 71 that accommodates the fixed piece 2, the movable piece 4, the thermal response element 5, the PTC thermistor 6, and the like. The case body 71 is attached. Thereafter, the case main body 71 and the lid member 81 are fixed by, for example, ultrasonic welding.

  FIG. 2 shows the operation of the breaker 1 in a normal charge or discharge state. In a normal charge or discharge state, the thermally responsive element 5 maintains the initial shape (before reverse warping), the fixed contact 21 and the movable contact 41 are in contact, and the breaker is connected through the first elastic portion 44 of the movable piece 4 and the like. 1 is electrically connected between the two terminals 22 and 42. The first elastic portion 44 of the movable piece 4 and the thermal responsive element 5 are in contact with each other, and the movable piece 4, the thermal responsive element 5, the PTC thermistor 6 and the fixed piece 2 are electrically connected as a circuit. However, since the resistance of the PTC thermistor 6 is overwhelmingly larger than the resistance of the movable piece 4, the current flowing through the PTC thermistor 6 is substantially larger than the amount flowing through the fixed contact 21 and the movable contact 41. It can be ignored.

  FIG. 3 shows the operation of the breaker 1 in an overcharged state or an abnormality. When a high temperature state occurs due to overcharge or abnormality, the thermally responsive element 5 that has reached the operating temperature is reversely warped, and the first elastic portion 44 of the movable piece 4 is pushed up, and the fixed contact 21 and the movable contact 41 are separated. At this time, the current flowing between the fixed contact 21 and the movable contact 41 is interrupted, and a slight leakage current flows through the thermal actuator 5 and the PTC thermistor 6. Since the PTC thermistor 6 continues to generate heat as long as such a leakage current flows, the resistance value is drastically increased while maintaining the thermally actuated element 5 in the reverse warping state, so that the current is a path between the fixed contact 21 and the movable contact 41. There is only the above-described slight leakage current (which constitutes a self-holding circuit). This leakage current can be used for other functions of the safety device.

  When the overcharge state is canceled or the abnormal state is resolved, the heat generation of the PTC thermistor 6 is also stopped, and the thermal actuator 5 returns to the return temperature and is restored to the original initial shape. Then, the movable contact 41 and the fixed contact 21 come into contact again by the elastic force of the first elastic portion 44 of the movable piece 4, the circuit is released from the interruption state, and returns to the conduction state shown in FIG. 2.

  FIG. 4 shows a case body 71 in which the fixed piece 2 is embedded. FIG. 5 further shows a case body 71 in which the PTC thermistor 6 and the thermally responsive element 5 are incorporated. The case main body 71 is provided with a first fixing portion 75 that is fixed to the lid member 81 and a second fixing portion 76 that is fixed to the movable piece 4. The first fixing portion 75 is continuously formed in a planar shape around the accommodation recess 73, that is, the openings 73a, 73b, and 73c. The second fixing portion 76 is formed facing the opening 73c. The second fixing portion 76 is formed in a planar shape at the bottom of the opening 73b. In the present embodiment, a step corresponding to the thickness of the movable piece 4 is provided between the first fixing portion 75 and the second fixing portion 76. By providing such a step on the lid member 81 side, the second fixing portion 76 may be formed on the same plane as the first fixing portion 75. Each step is set so that the sum of the step provided between the first fixing portion 75 and the second fixing portion 76 and the step provided on the lid member 81 side corresponds to the thickness of the movable piece 4. May be.

  The second fixing portion 76 has a depressed portion 77. The depressed portion 77 extends in a groove shape in the short direction of the breaker 1 along the edge of the opening 73c. The recessed portion 77 is recessed from the peripheral region 76a in a region facing the edge 5e (see FIG. 5) on the terminal 42 side of the thermally responsive element 5. Here, the peripheral region 76 a is a region located in the periphery of the region facing the edge 5 e of the thermally responsive element 5 in the second fixing portion 76. The depressed portion 77 is formed so as to be retracted from the end edge 5e of the thermally responsive element 5 to the outside of the opening 73c (on the side of the projection 74 and the terminal 42, that is, the side opposite to the movable contact 41). As already described, the opening 73c is provided in order to secure a movable region during thermal deformation of the thermally responsive element 5. Therefore, the depressed portion 77 is formed so as to be retracted outward from the movable region of the thermally responsive element 5. That is, the depressed portion 77 is provided outside the movable region of the thermally responsive element 5. In the present embodiment, the second fixing portion 76 has a stepped step between the depressed portion 77 and the peripheral region 76a. Between the depression 77 and the peripheral region 76a, a slope connecting the two may be formed.

  Since the second fixing portion 76 is formed with a depressed portion 77 that is depressed from the peripheral region 76 a in a region facing the edge 5 e of the thermal response element 5, the holding portion between the second fixing portion 76 and the movable piece 4. At the time of welding with 43, most of the molten resin is accommodated in the depression 77. Thereby, the resin flash which is the protrusion of the resin to the opening 73c of the case main body 71 is suppressed, and interference between the thermally responsive element 5 and the resin flash during the current interrupting operation is avoided. Therefore, the smooth operation of the thermally responsive element 5 and hence the movable piece 4 is ensured, and a good current interruption operation can be secured. Furthermore, in the present embodiment, the depressed portion 77 is formed by retracting from the end edge 5e of the thermally responsive element 5 to the outside of the opening 73c, so that interference between the thermally responsive element 5 and the resin beam is further avoided. .

  FIG. 6 shows the process of fixing the lid member 81 to the case main body 71 in the vicinity of the depressed portion 77 in an enlarged manner. 6A illustrates a process of attaching the lid member 81 to the case main body 71, and FIG. 6B illustrates a process of fixing the lid member 81 to the case main body 71.

  In the adhering step shown in FIG. 6B, the resin 78 generated by melting the resin of the second adhering portion 76 flows between the holding portion 43 of the movable piece 4 and the second adhering portion 76. A resin beam 78 a that protrudes from the resin 78 is formed at the edge of the flowing resin 78.

  As already described, the breaker 1 is provided with the depressed portion 77 in the second fixing portion 76 of the case main body 71. Therefore, the flowing resin 78 is accommodated in the depressed portion 77, and the generation of the resin flash 78a is suppressed. The The drop of the depressed portion 77 with respect to the second fixing portion 76 can be appropriately set according to the amount of the resin 78 that flows. The same applies to the depth of the depression 77 from the edge of the opening 73c. For example, in the example shown in FIG. 6, all of the flowing resin 78 is accommodated in the depressed portion 77, and the above-described drop and depth of the depressed portion 77 are such that the resin beam 78 a does not protrude from the depressed portion 77 toward the opening 73 c. Is set. The resin beam 78a may slightly protrude from the depressed portion 77 toward the opening 73c so that the edge 5e of the thermal response element 5B and the resin beam 78a do not interfere with each other.

  In the present embodiment, the bottom portion of the depressed portion 77 is formed above the end edge 5 e of the thermally responsive element 5, that is, on the holding portion 43 side of the movable piece 4. With such a configuration, the thickness of the case main body 71 below the depressed portion 77 is secured, and the rigidity and strength of the case main body 71 can be sufficiently increased.

  7 and 8 show modifications of the thermally responsive element 5 and the case main body 71. The heat-responsive element 5A shown in FIG. 7 has a cut end 51 that is cut linearly at a corner on the second fixing portion 76 side. The edge 5e of the thermal response element 5A is formed so as to extend in the short direction of the breaker 1 in the same manner as the edge 5e of the thermal response element 5 described above. Therefore, the depressed portion 77 of the case main body 71A is also the case described above. Similar to the depressed portion 77 of the main body 71, the thermal response element 5 </ b> A is formed over substantially the entire width in the short direction of the breaker 1. Even when the cut end 51 protrudes outside the diagonal line of the thermally responsive element 5, the depressed portion 77 is formed in the same manner as described above.

  The heat-responsive element 5 </ b> B shown in FIG. 8 has a protruding portion 52 that protrudes toward the second fixing portion 76, that is, the holding portion 43 side of the movable piece 4. Therefore, the edge 5e of the thermal response element 5B is the tip of the protruding portion 52. In the case main body 71B that accommodates such a thermoresponsive element 5B, a recessed portion 77 is formed in a region facing the protruding portion 52. That is, the protrusion 52 and the depression 77 are formed in a substantially similar shape in plan view. As a result, interference between the tip of the protrusion 52, that is, the edge 5e, and the resin beam 78a can be avoided.

  As described above, according to the breaker 1 of the embodiment according to the first invention, the movable piece 4 and the thermally responsive element 5 are accommodated in the resin case body 71 through the openings 73a, 73b, 73c, and the lid member 81 is provided. Is fixed to the case main body 71, the openings 73a, 73b, 73c are closed. The movable piece 4 has a clamping portion 43 that is clamped from the back and front by the case main body 71 and the lid member 81, and is accommodated on the front side of the thermally responsive element 5. The case main body 71 is formed with a second fixing portion 76 fixed to the back surface of the holding portion 43 so as to face the opening 73 c, and the movable piece 4 is firmly fixed to the case main body 71 and the lid member 81. Since the second fixing portion 76 has a depressed portion 77 that is depressed from the peripheral region in a region facing the end edge 5e of the thermally responsive element 5, the second fixed portion 76 is provided between the holding portion 43 of the movable piece 4 and the case main body 71. The resin 78 melted at the time of fixing to the two fixing portions 76 can be accommodated in the depressed portion 77. Thereby, the protrusion of the resin beam 78a to the opening 73c of the case main body 71 is suppressed, and the interference between the thermally responsive element 5 and the resin beam 78a during the current interruption operation is avoided. Therefore, the smooth operation of the thermally responsive element 5 and hence the movable piece 4 is ensured, and a good current interruption operation can be secured.

  Hereinafter, a breaker according to an embodiment of the second invention will be described with reference to the drawings. FIG. 9 shows the movable piece 4A applied to the breaker of the second invention from the back side. 4 A of movable pieces differ from the movable piece 4 of 1st invention by the point which has the recessed part 48 in the back surface of the clamping part 43. FIG. A breaker may be configured by combining the case main body 71 having the depression 77 and the movable piece 4A having the depression 48, or the case main body and the movable piece 4A not having the depression 77. The breaker may be configured by combining the above. Of the breaker of the second aspect of the invention, the configuration of the breaker 1 of the first aspect of the invention described above can be adopted for portions not described below.

  The depressed portion 48 is provided in a region facing the edge 5 e of the thermally responsive element 5. The depressed portion 48 is formed to be depressed from the peripheral region 43a. Here, the peripheral region 43 a is a region located in the periphery of the region of the sandwiching portion 43 that faces the edge 5 e of the thermally responsive element 5. The depressed portion 48 is formed by retreating from the end edge 5e of the thermally responsive element 5 to the outside of the opening 73c (on the side of the terminal 42 or the like, that is, the side opposite to the movable contact 41). Thereby, the back surface of the clamping part 43 has a stepped step between the depressed part 48 and the peripheral area 43a. Between the depression 48 and the peripheral region 43a, a slope connecting the two may be formed. Further, the first elastic portion 44 may be formed to a thickness equivalent to the depressed portion 48.

  Since the sandwiched portion 43 is formed with a recessed portion 48 that is recessed from the peripheral region 43 a, most of the resin 78 melted when the sandwiched portion 43 and the case body 71 are welded is accommodated in the recessed portion 48. The As a result, the resin beam 78a which is the protrusion of the resin 78 to the opening 73c of the case body 71 is suppressed, and the interference between the thermally responsive element 5 and the resin beam 78a during the current interruption operation is avoided. Therefore, the smooth operation of the thermally responsive element 5 is ensured, and a good current interruption operation can be secured.

  In the second invention, the movable piece 4A can be applied to a breaker in combination with the thermal response element 5A shown in FIG. 7 or the thermal response element 5B shown in FIG. For example, when combining the movable piece 4 </ b> A and the thermally responsive element 5 </ b> B, the depressed portion 48 is formed in a region facing the protruding portion 52. As a result, interference between the tip of the protrusion 52, that is, the edge 5e, and the resin beam 78a can be avoided.

  The present invention is not limited to the configuration of the above-described embodiment, and has a fixed piece 2 having a fixed contact 21 and a movable contact 41 at a tip end portion 4e, and the movable contact 41 is pressed against and brought into contact with the fixed contact 21. To accommodate the movable piece 4, the thermally responsive element 5 that operates the movable piece 4 so that the movable contact 41 is separated from the fixed contact 21 by being deformed as the temperature changes, and the movable piece 4 and the thermally responsive element 5. In the breaker 1 and the like provided with a resin-made case main body 71 having openings 73a, 73b, and 73c, and a lid member 81 and the like that are fixed to the case main body 71 in order to close the openings 73a, 73b, and 73c. What is necessary is just to have the structure of.

  That is, at least the movable piece 4 has a sandwiching portion 43 sandwiched from the front and back by the case main body 71 and the lid member 81 and is accommodated on the front side of the thermally responsive element 5 and the like. A second fixing portion 76 fixed to the back surface is formed to face the opening 73c, and the second fixing portion 76 is a depression that is depressed from the peripheral region 76a in a region facing the edge 5e of the thermal response element 5. What is necessary is just to have the part 77. FIG.

  At least the movable piece 4 </ b> A has a holding portion 43 that is sandwiched from the front and the back by the case main body 71 and the lid member 81, and is accommodated on the front side of the thermally responsive element 5. A second fixing portion 76 that is fixed to the opening 73c is formed so as to face the opening 73c, and the back surface of the sandwiching portion 43 is a recessed portion that is recessed from the peripheral region 43a in a region facing the edge 5e of the thermal response element 5. 48 is sufficient.

  The fixing method between the case main body 71 and the lid member 81 is not limited to ultrasonic welding, and any method can be applied as long as both are firmly fixed. For example, a liquid or gel adhesive may be applied, filled, and cured to bond them together. In this case, the adhesive is accommodated in the depressed portion 77 or 48, and the protrusion of excess adhesive to the opening 73c of the case main body 71 is suppressed, and interference between the thermally responsive element 5 and the adhesive during the current interruption operation is avoided. Is done. Further, the case 7 is not limited to the form constituted by the case main body 71 and the lid member 81, but may be constituted by two or more parts.

  Further, the shapes of the fixed piece 2, the movable piece 4, the thermally responsive element 5, the PTC thermistor 6, the housing recess 73, and the like are not limited to those shown in FIG. 1 and can be changed as appropriate.

  Further, as shown in Japanese Patent Application Laid-Open No. 2005-203277, the movable piece 4 is structurally separated into an arm terminal on the terminal 42 side and a movable arm on the movable contact 41 side in or near the clamping portion 43. The present invention may be applied to any form. Further, the arm terminal and the movable arm may be fixed by welding or the like. In this case, the clamping part 43, the 2nd elastic part 45, and the terminal 42 may be insert-molded by the case main body 71 with the fixed piece 2 grade | etc.,.

  Further, the breaker 1 of the present invention can be widely applied to secondary battery packs, safety circuits for electric devices, and the like. FIG. 10 shows a secondary battery pack 500. The secondary battery pack 500 includes a secondary battery 501 and a breaker 1 provided in the output terminal circuit of the secondary battery 501. FIG. 11 shows a safety circuit 502 for electrical equipment. The safety circuit 502 includes the breaker 1 in series in the output circuit of the secondary battery 501. According to the secondary battery pack 500 or the safety circuit 502 including the breaker 1, the secondary battery pack 500 or the safety circuit 502 that can ensure a good current interruption operation can be manufactured.

DESCRIPTION OF SYMBOLS 1 Breaker 2 Fixed piece 21 Fixed contact 4 Movable piece 4A Movable piece 41 Movable contact 48 Depressed part 5 Thermally responsive element 5A Thermally responsive element 5B Thermally responsive element 5e Edge 52 Protruding part 7 Case 71 Case main body (1st case)
73c Opening 76 Second fixing portion 77 Depressed portion 81 Lid member (second case)
501 Secondary battery 502 Safety circuit

Claims (5)

A fixed piece having a fixed contact;
A movable piece having a movable contact at a tip, and pressing the movable contact against the fixed contact; and
A thermally responsive element that operates the movable piece so that the movable contact is separated from the fixed contact by being deformed with a temperature change;
A first case made of resin having an opening for accommodating the thermally responsive element;
In a breaker comprising a second case fixed to the first case to close the opening,
The movable piece has a sandwiching portion that is sandwiched from the back and front by the first case and the second case, and is housed on the front side of the thermally responsive element,
In the first case, a fixing portion fixed to the back surface of the clamping portion is formed facing the opening,
The fixing unit includes a death portion Recessed in a region opposed to the edge of the heat responsive element,
The breaker is formed of a breaker that is depressed from the fixed portion around the depression and is retracted from the edge to the outside of the opening. A fixed piece having a fixed contact;
A movable piece having a movable contact at a tip, and pressing the movable contact against the fixed contact; and
A thermally responsive element that operates the movable piece so that the movable contact is separated from the fixed contact by being deformed with a temperature change;
A first case made of resin having an opening for accommodating the thermally responsive element;
In a breaker comprising a second case fixed to the first case to close the opening,
The movable piece has a sandwiching portion that is sandwiched from the back and front by the first case and the second case, and is housed on the front side of the thermally responsive element,
In the first case, a fixing portion fixed to the back surface of the clamping portion is formed facing the opening,
The back surface of the sandwiching portion, sinking portion is provided Recessed in a region facing the edge of the heat responsive element,
The breaker is depressed from the sandwiching portion around the depression . The edge of the thermally responsive element has a protruding portion that protrudes toward the clamping portion,
The breaker according to claim 1, wherein the depressed portion is formed in a region facing the protruding portion.   A safety circuit for electrical equipment, comprising the breaker according to any one of claims 1 to 3.   A secondary battery circuit comprising the breaker according to claim 1.

Images